RADIATION PROTECTION OF WORKERS Radioactive … · RADIATION PROTECTION OF WORKERS Radioactive...
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IF CONTAMINTATION IS PRESENT DOSE AND EFFECTS þ PROCEDURES EXTERNAL EXPOSURE INTERNAL EXPOSURE External exposures to staff can occur: When handling primary or stock solutions. When handling transport packages. When cleaning up radioactive contamination. When working near a source storage facility. þ þ þ þ Storage When radioactive material is not in use, it must be properly stored. A good storage location will be: Only used to store radioactive material. Secure. Shielded. Labelled. þ þ þ þ A contaminated person should: Stay where he/she is. Call for help and alert the Radiation Protection Officer. Do not touch anything. Not enter the area unless an injured person needs help. Start decontamination procedures only when trained. þ þ þ þ þ Users should measure the dose rate around storage locations, around primary or stock solutions, or wherever there are large quantities of radioactive material. It is important to check for contamina- tion in the work area and on the hands of the users at regular intervals while radioactive material is being used. At the end of a period of work, the work space must be thoroughly checked for contamination. RADIATION MONITORING Survey meters are very important in helping to keep exposures As Low As Reasonably Achievable: ALARA Time To reduce radiation doses, the time spent in radiation areas must be kept as short as possible. The longer the time spent in an area, the higher the dose received. In an area where the dose rate is 100 ìSv/h, the dose received will be: Distance 1 cm of plastic will totally shield all beta radiation. Lead and concrete can be used to shield against gamma and X radiations. Shielding material must be appropriate for the type of radiation. For example: 0 minutes 15 minutes 30 minutes 1 hour 2 hour 0 μSv 25 μSv 50 μSv 100 μSv 100 μSv/h 200 μSv Shielding plastic lead concrete 1 m 2 m 25 μSv/h If the dose rate at 1 m from a source is 100 /h. μSv/h, the dose rate at 2 m will be 25 μSv Radioactive material can enter the body by inhalation, ingestion and absorption through intact or damaged areas of the skin. The presence of radioactive contamination presents an internal exposure risk to staff for each of these exposure routes. There may be contamination: CONTAMINATION þ þ þ þ þ þ þ þ þ þ þ þ Where splashes or spills have occurred. On the inner surfaces of used vials or other containers. On laboratory surfaces. On the hands of users. Where there is radioactive contamination you should: Wear plastic gloves. Wear protective glasses. Cover cuts and wounds. Never eat, drink, smoke or apply cosmetics. Clean up spills, even minor splashes as soon as practicable. Not touch things unnecessarily. Wash your hands at the end of the period of work. Contact the Radiation Protection Officer. Others must: Marking and labeling Source containers should be labelled “Radiaoctive Material”. The name of the radioisotope, the activity and the trefoil warning symbol should also be shown. Transport Radioactive material will be transported in a package that complies with national and international regula- tions. The package will be labelled according to the dose rate. Dosimeters A dosimeter is a means of assessing the dose that the wearer has received. Dosimeters should be worn between the shoulders and the hips and must be returned to the provider regularly so that the dose information can be read. Sometimes, dosimeters are worn on a finger, underneath the gloves, to assess the dose to the hand. External exposures can be controlled by consideration of time, distance and shielding. DOSE RATE INCREASES Source records A record must be kept of all radioactive material held on-site at any given time. The record must track the radioactive material throughout a process, up to and including its disposal. Waste Any radioactive waste must be disposed of according to strict procedures that follow regulations and requirements. Records must be kept of all radioactive waste. RADIATION PROTECTION OF WORKERS Radioactive tracers are substances labelled with a radioactive atom that allow easier detection and measurement. They are used in the oil and gas, chemical, food and tobacco industries as well as in the management of water resources, in scientific research and in medical applications. In use, they can present an external exposure or, if the radioactive material enters the body, an internal exposure. DOSE ASSESSMENT Units of dose Dose rate Health effects of radiation exposure The unit of absorbed dose is the gray (Gy). The unit used to quantify the dose in radiation protection is sievert (Sv). One millisievert (mSv) is 1/1000 of a sievert. One microsievert ( Sv) is 1/1000 of a millisievert. Dose rate is the dose received in a given time. The unit used is microsieverts per hour ( Sv/h). If a person spends two hours in an area where the dose rate is 10 μSv/h, then they will receive a dose of 20 μSv. Annual doses from natural background radiation vary on average between 1 mSv and 5 mSv, worldwide μ The typical dose from a chest X ray is 20 μSv. μ If radiation doses are very high, the effect on the body will appear relatively soon after the exposure. These acute injuries will occur if the absorbed dose is higher than a threshold value; some sources used as radioactive tracers are capable of delivering such doses. It is therefore essential that procedures for work are followed. Even if the dose is not high enough to cause serious injury, there is still the possibility of incurring other health effects. These effects, e.g. radiation induced cancer, are risk based, i.e. the higher the dose received, the greater the chance of developing the effect. To reduce the possibility of developing late effects, radiation doses must be kept: AS LOW AS REASONABLY ACHIEVABLE (ALARA) Radioactive Tracers
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Transcript of RADIATION PROTECTION OF WORKERS Radioactive … · RADIATION PROTECTION OF WORKERS Radioactive...
IF CONTAMINTATION IS PRESENT
DOSE AND EFFECTS
þPROCEDURES
EXTERNAL EXPOSURE
INTERNAL EXPOSURE
External exposures to staff can occur:
When handling primary or stock solutions.
When handling transport packages.
When cleaning up radioactive contamination.
When working near a source storage facility.
þ
þ
þ
þ
Storage
When radioactive material is not in use, it must beproperly stored. A good storage location will be:
Only used to store radioactive material.
Secure.
Shielded.
Labelled.
þ
þ
þ
þ
A contaminated person should:
Stay where he/she is.
Call for help and alert the Radiation ProtectionOfficer.
Do not touch anything.
Not enter the area unless an injured personneeds help.
Start decontamination procedures only whentrained.
þ
þ
þ
þ
þ
Users should measure the dose ratearound storage locations, aroundprimary or stock solutions, or whereverthere are large quantities of radioactivematerial.
It is important to check for contamina-
tion in the work area and on the hands
of the users at regular intervals while
radioactive material is being used. At
the end of a period of work, the work
space must be thoroughly checked for
contamination.
RADIATION MONITORING
Survey meters are very important in helping to keep exposures
As Low As Reasonably Achievable: ALARA
Time To reduce radiation doses, the time spent in radiationareas must be kept as short as possible. The longer the timespent in an area, the higher the dose received.In an area where the dose rate is 100 ìSv/h, the dosereceived will be:
Distance
1 cm of plasticwill totally shield allbeta radiation.
Lead and concrete canbe used to shield againstgamma and X radiations.
Shielding material must be appropriate forthe type of radiation. For example:
0 minutes 15 minutes 30 minutes 1 hour 2 hour
0 µSv 25 µSv 50 µSv 100 µSv
100 µSv/h
200 µSv
Shielding
plastic lead concrete
1 m
2 m
25 µSv/h
If the dose rate at 1 m from a source is 100/h.
µSv/h,the dose rate at 2 m will be 25 µSv
Radioactive material can enter the body by inhalation,ingestion and absorption through intact or damaged areas ofthe skin. The presence of radioactive contaminationpresents an internal exposure risk to staff for each of theseexposure routes.
There may be contamination:
CONTAMINATION
þ
þ
þ
þ
þ
þ
þ
þ
þ
þ
þ
þ
Where splashes or spills have occurred.
On the inner surfaces of used vials or other containers.
On laboratory surfaces.
On the hands of users.
Where there is radioactive contamination you should:
Wear plastic gloves.
Wear protective glasses.
Cover cuts and wounds.
Never eat, drink, smoke or apply cosmetics.
Clean up spills, even minor splashes as soon aspracticable.
Not touch things unnecessarily.
Wash your hands at the end of the period of work.
Contact the Radiation Protection Officer.
Others must:
Marking and labeling
Source containers should be labelled “RadiaoctiveMaterial”. The name of the radioisotope, the activityand the trefoil warning symbol should also be shown.
Transport
Radioactive material will be transported in a packagethat complies with national and international regula-tions. The package will be labelled according to thedose rate.
Dosimeters
A dosimeter is a means of assessing thedose that the wearer has received.Dosimeters should be worn between theshoulders and the hips and must bereturned to the provider regularly so thatthe dose information can be read.Sometimes, dosimeters are worn on afinger, underneath the gloves, to assessthe dose to the hand.
External exposures can be controlled by considerationof time, distance and shielding.
DOSE RATE INCREASES
Source records
A record must be kept of all radioactive material heldon-site at any given time. The record must track theradioactive material throughout a process, up to andincluding its disposal.
Waste
Any radioactive wastemust be disposed ofaccording to strictprocedures that followr e g u l a t i o n s a n drequirements. Recordsmust be kept of allradioactive waste.
RADIATION PROTECTION OF WORKERS
Radioactive tracers are substances labelled with aradioactive atom that allow easier detection andmeasurement. They are used in the oil and gas, chemical,food and tobacco industries as well as in the managementof water resources, in scientific research and in medicalapplications. In use, they can present an external exposureor, if the radioactive material enters the body, an internalexposure.
DOSE ASSESSMENT
Units of dose
Dose rate
Health effects of radiation exposure
The unit of absorbed dose is the gray (Gy).
The unit used to quantify the dose in radiationprotection is sievert (Sv).
One millisievert (mSv) is 1/1000 of a sievert.
One microsievert ( Sv) is 1/1000 of a millisievert.
Dose rate is the dose received in a given time.The unit used is microsieverts per hour ( Sv/h).
If a person spends two hours in an area where thedose rate is 10 µSv/h, then they will receive a dose of20 µSv.
Annual doses from natural background radiation varyon average between 1 mSv and 5 mSv, worldwide
µ
The typical dose from a chest X ray is 20 µSv.
µ
If radiation doses are very high, the effect on the body willappear relatively soon after the exposure. These acuteinjuries will occur if the absorbed dose is higher than athreshold value; some sources used as radioactivetracers are capable of delivering such doses. It istherefore essential that procedures for work arefollowed.
Even if the dose is not high enough to cause seriousinjury, there is still the possibility of incurring other healtheffects. These effects, e.g. radiation induced cancer, arerisk based, i.e. the higher the dose received, the greaterthe chance of developing the effect. To reduce thepossibility of developing late effects, radiation dosesmust be kept:
AS LOW AS REASONABLY ACHIEVABLE (ALARA)
Radioactive Tracers
